drivers/gpio/vx855_gpio.c needs slab.h

alpha allmodconfig:

  drivers/gpio/vx855_gpio.c: In function 'vx855gpio_probe':
  drivers/gpio/vx855_gpio.c:233: error: implicit declaration of function 'kzalloc'
  drivers/gpio/vx855_gpio.c:233: warning: assignment makes pointer from integer without a cast

Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/gpio/vx855_gpio.c

@@ -26,6 +26,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/gpio.h>
+#include <linux/slab.h>
 #include <linux/device.h>
 #include <linux/platform_device.h>
 #include <linux/pci.h>